A method for producing pouches comprising the steps of providing a continuous web, folding the web to provide confronting side surfaces joined along a bottom edge and forming a vertical seal between the confronting side surfaces, thereby providing a series of adjacent pockets having opposite side walls, with each pocket having an unsealed opening along a top edge, and filling the pockets through the opening with material and then sealing the opening to provide sealed pouches is known from WO 2007/089838 A2.
In the known method, the continuous web is guided through a vertical sealer in which the vertical seals are formed after the continuous web has been folded. Those vertical seals are spaced from one another to provide a pocket which is defined by the bottom edge as the bottom of the pocket and a leading edge which is defined by a vertical seal, and a trailing edge which is defined by the neighboring vertical seal. The vertical seal is provided such that neighboring pockets can be separated without impeding the closure of the pocket by the vertical seal. By separating the pockets, individual pouches are formed.
In the method known from WO 2007/089838 A2, the continuous web is transferred to a cutting section in which the continuous web is cut to isolate individual pouches having an unsealed opening along the top edge. Those pouches are transferred by a vacuum belt transport means against which the separated pouches are sucked and transferred to a filler wheel. The filler wheel has gripping elements which are adapted to grip the leading and tailing edges of each pouch, respectively, between jaws and are movable relative to each other to open the unsealed opening. As the distance between the leading and the tailing edges of one single pouch is reduced, the distance between the confronting side surfaces in increased. Accordingly, spouts of a spout wheel can be introduced into the pouches for filling the same with material. The spout wheel and the filler wheel are rotatably driven. The rotational axis of the filler wheel is essentially co-axial to the rotational axis of the spout wheel. However, the rotational axes are slightly inclined relative to each other. At a circumferential section in which the distance between the spout wheel and the filler wheel is at its minimum, a respective spout is received within the open mouth of the pouches and then continuously retracted from the pouch as the filler wheel and the spout wheel are continuously rotated, starting from this position.
After the pouches have been filled, the gripping means are actuated such that the distance between the leading and the tailing edges of the each spout are increased, thereby bringing the confronting side surfaces closer together and closing the unsealed opening. In the course of the circular path along the outer circumference of the filler wheel, the pouches are finally sealed by a sealing section arranged at the outer circumference of the filler wheel and provided with heated sealing surfaces abutting against the folded web material for sealing the opening.
The method known from WO 2007/089838 A2 and the apparatus for carrying out said method is disadvantageous in that it requires a fusible film material for making the web. Fusible film materials are not suitable for making a packaging for e.g. tea, coffee or the like, because these substances have to be brewed while still contained in the pouch. Further, fusible film materials usually require a plastic material for forming the web or at least a plastic coating on the web, which may be disadvantageous for ecological reasons in case the material has to breathe.
Further, the apparatus known from WO 2007/0898238 A2 has a complex constitution, which may be troublesome due to the fact that each pouch is gripped at its leading and trailing edge by a gripping unit. The gripping unit makes manufacturing of the apparatus for carrying out the packaging method expensive. The vacuum belt transport means add to the rather complex constitution of the known apparatus. Further, handling of isolated pouches may cause problems, in particular if pouches are to be made in a fast and economic way.
U.S. Pat. No. 4,534,185 A is a further example of a method in which pouches are formed from a continuous web and then transferred as individual items to a filler wheel in which the pouches are filled with material, then sealed and finally discharged from the filler wheel as sealed pouches. The drawbacks of the apparatus and the method known from this prior art document are essentially the same as the ones discussed with reference to WO 2007/089838 A2. A similar method and apparatus are disclosed in JP 11 292001 A.
U.S. Pat. No. 3,563,001 A is an example of an apparatus and a method in which vertical seals are formed on a wheel defining a vertical filler. The continuous web providing pockets between the vertical seals and a bottom edge is continuously conveyed to a filler wheel in which the pockets are filled with material, essentially in the same way as discussed above with reference to WO 2007/089838 A2. The continuous web is transferred from the circular path around the filler wheel to a linear path and to a top sealer in which the unsealed opening of the pockets is sealed. Then, the continuous web is twisted such that the vertical orientation of the web is transferred into a horizontal orientation. In said horizontal orientation, the web is conveyed to a cutting table on which the material defining the pockets is cut at the vertical seal to thereby isolate individual sealed pouches, which are made to slide from the cutting table.
A respective apparatus and method is described e.g. in U.S. Pat. No. 5,502,951 A, U.S. Pat. No. 3,597,898 A, CA 2 142 480 A1 or U.S. Pat. No. 6,058,818 A. The aforementioned prior art with a separate cutting station for separating the pouches from a continuous web are bulky. Furthermore, pouches separated on the cutting table have to be collected after cutting in order to further process the individual pouches. In other words, the predetermined orientation and holding of individual pouches is lost during cutting, making processing of the filled and sealed pouches troublesome.
The present invention aims to provide a method form making pouches and a packaging apparatus for making pouches by at least partially avoiding the aforementioned disadvantages and drawbacks. In particular, the present invention aims to improve the method known from WO 2007/089838 A2 such that transfer of the web to the filler wheel is facilitated, and to improve the packaging apparatus in particular to reduce complexity and bulkiness of the apparatus known from WO 2007/089838 A2.